Spark-plug.



C. H. DUFFY.

SPARK PLUG. I APPLICATION FILED JULY 30, I917- Patented Mar.26,1918.

To all wit-ozt concern:

Be it known that l {II-mews HUGE Derry, a citizen of the United States,- residing at Chevy Chase in the county of Montgomery and Estate of Murylznid, have invented certain new and useful Improve ments in Spsrlnl lngs; end I do declare the following to he a toll, clear and exact description of the invention, such us will enable others skilled in the art to which it cppertnins to make and use the some, reterencebeing had to the accompanying draw ings, and to tholettcrs and figures of erence marked thereon, which form part oi this specification.

'lhis-invention relates to fiplll'li' plugs "tor internal combustion engines, and has tor its object to provide it device of this class which embodies improvements in the method, con structionand arrangement for seating and maintaining the insulating core Within the metal shell of the plug; to prevent leakage of pressure.

The invention consists in the novel construction and arrangement of the core holding gland and in the method .or efi'ecting the retention of the core within the some and of effecting s gas tight union between the gland and the metal shell and between the gland and the core.

Referring to the accompanying drewing Figure 1 is a, vertical sectional View of a spark phi constructed in accordance with this invention 7 Fig. 2 is a fragmentary sectional View illustrating the manner of assembling the gland and. core in the shell.

3 is an elevation of the gland and core after being assembled.

Fig". 4: is an elevation of the gland before entering the shell.

Figv 5 is n bottom plan View of the shella and Fig. 6 is a vertical sectional VlGW showing the shell, gland and core in an assembled position.

Like numerals of reference indicate the same parts throughout the several figures, in Which:-

1 indicates the spank plug comprising the threade metal shell 2, gland 8, insulating core 4. central electrode 5 and ground clectrode 6.

The core 4- loes en enlorged. control ring '9 Specification of tters July 30, 191.7.

item

Serial. No.

forming a list shoulder 10 at its top and pref ernhly :1 55 shoulder 11 at its bottom, and is centrally epertnred at 16 to receive the thread l central. electrode Referring to the gland 21, it will be seen that the SHIDO is provided with a, lintted portion n depending thin tubular or thin1- hlc portion and an intermediate threaded portion 2 t for connection with the internally threaded sh ll 2, While internally ot the gland at the beginning of the thin tnonlnr portion 23 i: e shoulder 25, the edge of said portion being pretr-srnhly rounded at 26.

The shell 2 is externally tln'eadednt 2? for connection with :1 motor. and is provided intermediate its ends with n down'wardly inclined :ninulnr shoulder 28, the shell being" nportnred to receive the core 1; and glmid 21 in the manner ns shown in 1.

ln assembling the plug, the core and centrsl electrode are secured in proper position and the core at is placed in the gland 21, :1 being;- preferebl'y provided between the shoulder 10 of the core at ltll'cl tl mouldcr 25 of the gland 21, the thin depending tuhn lur portion 223 c. tending? slightly beyond the inclined shoulder ll or the core, while a gasket 26 is placed as shown in llig. 2. lVhon in this position the gland 21 end core lare inserted in the shell 2, the opero-- tion being fnc'rilitnted it the ports are held upside down. The gland 21 tin-curled intm the shell 2 so that the rounded edge 26 of the tubular extension 2 5 impinges on the inclined shoulder 28 as shown in Fig. 2. Further rotation of the gland 21 senses it to progress inwardly oi? the shell 2 and the rounded edge 26 ot the gland 2t is gradually spun innu irdly as shown in Fig. 3, by the shoulder 28 until the entire end portion 26 of the thin tubular portion 21 is spun on the inclined shonlder until the entire end portion 26 of the thin tnhulor portion 23 is spun under the gasket 36 end the inclined shoulder 11 of the core i. As this spinning operation is heing elt'ected and the inward progress of the core lis being retarded. by the tnrni 11;; under of the tubular portion 23, the gaskets and 36 are compressed. As the portion 26 is spun under the shoulder 11 of the core. as it is lacing rotated on the inclined shoulder 28 of the shell, said portion 26 conforms to the said shoulder 28 and grinds a hearing thereon in such manner that a gas tight onion is formed hetween the shoulder 28 and the spun portion 26, while a gas tight joint is simultaneously effected between the core 4 and the gland 21, at the gaskets 35 and 36. This method of spinning the gland directly on the inclined shoulder 28 of the shell 2 presents the advantage that an absolute conformation of thespun portion 26 with the shoulder 28 is oduced and a ground bearing ell'ected Which is not so obtained by spinning the glandon the core 4 by usual mechanical means, as in the ordinary manner there would be no assurance of a gas tight joint and the employment of a gasket between the portion 26 and theshoulder 28 would be quite necessary.

Having thus fully described the invention what I claim and desire to secure by Letters Patent of the United States is:

1. A spark plug comprising a metal shell threaded for connection with a motor and having an internal bore, and an internal shoulder, an insulating core and suitable electrodes, a gland for connection with said shell, a tubular portion on said gland and an internal shoulder, said tubular portion being adapted to receive said insulating core, the end of said tubular portion being adapted to engage the said shoulder in said shell to spin said end of said tubular portion under said insulating core and between the same -and said shoulder in said shell.

2. A spark plug comprising a metal shell having a bore therein and an internal shoulder, an insulating core having a central ring forming an upper and a lower shoulder, a gland for connection with said shell and having an internal shoulder and a tubular portion to receive said insulating core, the lower end of said tubular portion being adapted to engage said shoulder in said shell to spin the same under said ring and bletfireen the same and said shoulder in said s e 3. A spark plug comprising a metal shell having a shoulder therein, an insulating core havin a ring thereon, a land having a shoulder t erein and a tubu ar portion to receive said insulating core, said tubular portion being adapted to engage and rotate on said shoulder in said shell to spin said tubular portion under said ring and to grind a gas tight joint between the spun tfiblullar portion and said shoulder in said s e 4. A spark plug comprising a metal shell having a shoulder therein, a gland for connection with said shell, an insulating core to be received by said gland, a tubular portion in said gland adapted to engage said shoulder in said shell and to rotate thereon to spin the tapered portion under said insulating core.

5. A spark plug comprising a shell, an

reaches insulating core and a gland provided with a tubular portion adapted to receive said insulating core, means within said shell to be engaged by said tapered portion of said gland to spin the same around said insulating core upon the inward progression of said gland within said shell.

6. A spark plug comprising a shell having a shoulder therein, an insulating core having a ring thereon forming an upper and a lower shoulder,'a gland for connection with said shell and provided with an internal shoulder and a tubular portion, said insulating core being adapted to be received 7 by said gland, packing means between theshoulder in said gland and the upper shoulder in said insulating core, the said 7 tubular portion of said gland being adapted to engage said shoulder in said shell and to rotate thereon to spin said tubular portion under the lower shoulder of said insulating core and to grind a gas tight joint between the shoulder in said shell and the tubular portion of the gland.

7 The herein described method ofseat ing an insulating core in a spark plug'shell with consists in inserting the insulating core in a threaded gland or bushing, in threading the gland or bushing into the spark plug shell to rotate the gland or bushing against a shoulder in the spark plug shell to spin the said gland or bushing under the insu lating core and between the same and the shoulder in the spark plug shell.

8. The herein described'method of seating an insulating core in a spark plug shell, which consists in providing a spark plug shell with an internal shoulder and in proi viding a core retaining gland tubular portion, in inserting the insulating core within its retaining gland and in rotating the gland against the shoulder in the shell to spin the tubular portion of the gland with a thin between the insulating core and the shoulder J which consists in relatively progressing a' threaded core retaining gland inwardly of a spark plug shell and against ashoulder therein to distort the said threaded core retaining gland and spin thexsame between the insulating core and the spark plug shell.

11. The herein described method of remining an insulating core within a spark In testimony whereof I afix my signature plug gland, which consists in relatively proin presence "of two witnesses.

wardly of a, shell and against a shoulder gressing a threaded core retaining gland inv CLES HUGH therein, to distort the said threaded core re- I In-presence 0ftaininglgland and spin the same between the FLORENCE A. BARhQN.

insulating cere and the shoulder in the shell. s M. A. BERGMANN. 

